Movement (e.g., flexion and extension) of the natural human knee involves movement of the femur and the tibia. Specifically, during flexion and extension, the distal end of the femur and the proximal end of the tibia articulate relative to one another through a series of complex movements. Damage (e.g., trauma) or disease can deteriorate the bones, articular cartilage, and ligaments of the knee, which can ultimately affect the ability of the natural knee to function in such a manner. As a result, knee prostheses have been developed and implanted into surgically-prepared ends of the femur and tibia.
A typical knee prosthesis for a total knee replacement, for example, includes a tibial component or tibial tray coupled to the patient's tibia, a femoral component coupled to the patient's femur, and a tibial insert component positioned between the tibial tray and the femoral component and including a surface to accommodate the condyles of the femoral component. A constrained knee prosthesis, however, may be used when a patient's collateral ligaments have been damaged or are otherwise not able to provide adequate support and stability to the knee. One such constrained knee prosthesis is a hinged knee prosthesis, which typically includes a hinge mechanism to couple the femoral component to one or both of the bearing component and the tibial components in order to constrain and mechanically link the components of the knee prosthesis together. Existing hinge knee designs require either a dedicated hinge knee femoral component, or require the hinge axle to be inserted into the femur, which can be difficult if there is not adequate exposure to hinge axle.